1. Field of the Invention
The present invention relates to an operation microscope which magnifies an object in order to perform a desired operation while observing the magnified object. More specifically, the invention relates to a microscope for surgery which is used to observe stereoscopically an observation object such as an eye of a patient, in ophthalmic, encephalic, or other medical diagnosis, treatment and surgery, or to an industrial stereoscopic microscope for processing and checking electronic parts, etc.
2. Description of Related Art
Conventionally, binocular stereoscopic microscopes with which a surgery region such as an eye of a patient can be stereoscopically observed as an observation object are widely used in ophthalmic surgery, encephalic surgery, etc. In such a binocular stereoscopic microscope for surgery, a branch observation optical system is provided. The branch observation optical system is branched from a main observation optical system that is used by an operator to observe an observation object, with the intention of making it possible for an assistant to assist the operator or for an intern to study the ongoing surgery.
In a case where, for instance, an operator gives a treatment in ophthalmic surgery on a certain region of a patient's eye using tweezers, a scalpel, etc., the operator pays attention not only to the region treated but also to other regions, and keeps watching over an undesirable sign of the patient's eye during the treatment. Namely, the apparent field of a microscope for surgery sometimes reaches up to 50 degrees, and though the subject region of the treatment may occupy merely a part of that field of view at some point in the treatment, the operator gives attention to the entire field of view of the microscope, not the partial field of view thereof.
Meanwhile, the operator may give instructions to assistants regarding to treatment or operation of the surgery, or explanations to observers regarding to a method or procedure of the surgery. Such instructions or explanations often cover regions other than the region to be treated.
Unfortunately, there are considerable difficulties for the operator in wording a region that is the subject of the operator's instructions or explanations. For that reason, with a conventional microscope for surgery, the operator has to stop the surgery for a while to indicate the region concerned using tweezers or the like, which involves inconvenience of hindering quick completion of the surgery.